A novel speckle patterns processing method is presented using multi-scale wavelet techniques. Laser speckle patterns
generated from the sample contained abundant information. In this paper, we propose a method using wavelet entropy
techniques to analyze the speckle patterns and exact the information on the sample surface. In our case, we used this
approach to test the solar silicon cell surface profiles based on the sym8 orthogonal wavelet family. According different
wavelet entropy values, the micro-structure of different solar silicon cell surfaces were comparative analyzed.
Furthermore, we studied the AFM and reflective spectra of the wafer. Results show that the wavelet entropy speckle
processing method is effective and accurate. And the experiment proved that this method is a useful tool to investigate
the surface profile quality.
An optical system with double beam interference system was designed to measure the movement of nano-particles in fluid with laser speckle technology. In order to investigate the influence of the scattering light generated from liquid surface on speckle patterns, the liquid surface contour was dynamically detected by WYKO during nano-particle movement. The result demonstrates that the fluctuation of fluid surface is slight. Meanwhile, in order to further analyze this effect, a piece of ground glass was employed. The process of ground glass to be polished to optical glass was studied and tested continuously using WYKO and laser speckle technology. And then, the speckle patterns generated from kerosene fluid surface were studied.
By contrast, the results show that, the fluid surface is transparent to the measurement wavelength. The influence of the surface of fluid can be neglected. Furthermore, the conclusion illustrates that laser speckle technique is an effective and reliable method to study the movement of nano-granular in fluid.